JP2023549018A - Reusable, biodegradable and industrially compostable extruded foam and method for making the same - Google Patents

Abstract

The process for producing flexible foams is characterized in that the masterbatch material is essentially one that is recycled, recyclable, biodegradable and/or compostable. or introducing a masterbatch material consisting of a plurality of thermoplastic polymers into an extruder, mixing an inert gas with the masterbatch material, and extruding the masterbatch material through the extruder to form a polymer melt. passing the polymer melt through a die to form an extrudate; and expanding the extrudate into a foam.

Description

Cross-reference of related applications
[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63/114,051, filed November 16, 2020, which is incorporated herein by reference in its entirety.

[0002] The present disclosure provides, according to some embodiments, forming flexible foams from recycled, recyclable, biodegradable, bio-based and/or industrially compostable materials. Regarding the process of In some embodiments, the present disclosure provides an extrusion process for forming flexible foams. Foams made according to embodiments of the present disclosure can be used in a variety of industries and end products, including, but not limited to, footwear components, seating components, armor components, vehicle components, bedding, and water sports accessories. Can be useful.

[0003] Flexible foam is a type of object formed by trapping pockets of gas in a liquid or solid, and the resulting foam is flexible in part due to its malleability. It is said that it is sexual. Flexible foams are typically used in cushioning applications such as footwear, furniture, bedding, and other sports equipment. Flexible foams typically fall into two categories: closed cell flexible thermoplastic polymer foams and open cell flexible polyurethane foams. Each of these foam types has very different manufacturing methods.

[0004] Closed cell flexible thermoplastic polymer foams are generally produced in a dry process in which an appropriate synthetic polymer is selected and various chemical additions are made to produce the "dough". compound, crosslinking agent and chemical blowing agent. The dough is then kneaded and extruded into flat sheets. The sheets are then stacked on top of each other and placed in a heated press under controlled pressure. This mixture of material and chemical blowing agent reacts and expands inside the heated press cavity. The result is a "bun" or "block" of closed-cell flexible foam, which is then sliced to a predetermined thickness. In contrast, open cell flexible polyurethane foams are typically manufactured in a liquid injection or liquid molding process in which artificial polyol chemicals, isocyanate chemicals and other chemical additives are It is allowed to react while being poured or sprayed into a molded shape such as a "bun" or "block." The result is an open-cell flexible foam, which is then sliced to a predetermined thickness.

[0005] A problem with flexible foams currently available on the market today is that these foams are almost exclusively made with non-recyclable and non-compostable materials and/or environmentally hazardous materials. This means that chemical substances are used. Furthermore, due in part to the chemical cross-linking that occurs in the above-described methods of producing conventional flexible foams, the physical structure of these flexible foams cannot be easily recycled or composted. This is due in large part to the chemical composition of the foam design and its inability to separate back into the underlying precursor components. That is, at the end of the life of a conventional flexible foam, the foam has no further use and cannot be successfully reprocessed into new materials in any known commercially viable manner.

[0006] The present disclosure may be used to manufacture reusable, biodegradable, compostable, sustainable and/or environmentally responsible end products, according to some embodiments. , provides flexible foams and manufacturing processes. In some embodiments, the foam material and the final product are both capable of sustained use without degradation, but are easily recyclable and/or compostable at the end of their life.

[0007] Compared to more conventional manufacturing processes, an objective of the manufacturing process disclosed herein is that the manufacturing process yields an environmentally friendly final product. By choosing recycled and/or recyclable or biodegradable and industrially compostable raw materials to produce polymers, embodiments of the present disclosure contribute to the so-called circular economy. This can significantly reduce the amount of waste that ends up in landfills each year. In a preferred embodiment, the flexible foam is obtained from recycled materials and is recyclable at the end of its pot life. Therefore, the selection of environmentally sustainable materials used in the manufacture of the final product should be carefully considered and balanced with the intended performance and pot life of the final product.

[0008] For example, running shoes are highly technical products that are exposed to repeated abuse, including impact, abrasion, and all forms of environmental exposure, over a significant period of time, perhaps 1 to 3 years depending on frequency of use. It is. When selecting sustainable materials for use in the manufacture of cushioning for running shoe soles, midsoles, and/or insoles, it is important to consider the above factors. Materials that cannot withstand repeated abuse before failure will not produce a satisfactory pair of running shoes. Additionally, any material that has the potential to degrade or weaken to the point of failure during normal product use prior to the end of its intended life is unacceptable.

[0009] To solve this problem, embodiments of the present disclosure utilize certain materials that provide a balance of technical performance characteristics and sustainability aspects. These sustainability aspects include, for example, properties such as reusability or compostability with controlled end-of-life solutions. In some embodiments, the materials used in this disclosure are net neutral (or negative) with respect to harmful emissions. A final product comprising a reusable or compostable flexible foam formed in accordance with embodiments of the present disclosure should perform very well over the product's pot life and at the end of the product pot life. Only materials have the option of being directed to reuse or composting settings for "closed-loop" waste conversion.

[0010] In some embodiments, the process for manufacturing a flexible foam comprises a masterbatch material, wherein the masterbatch material is essentially recycled, recyclable, biodegradable. introducing a masterbatch material comprising one or more thermoplastic polymers that are thermoplastic and/or compostable into an extruder; and mixing an inert gas with the masterbatch material to form a polymer melt. the step of extruding the masterbatch material through an extruder, passing the polymer melt through a die to form an extrudate, and expanding the extrudate into a foam. In some embodiments, the inert gas is nitrogen. In other embodiments, the inert gas is carbon dioxide.

[0011] In some embodiments, the one or more thermoplastic polymers are polyamides or polyamide copolymers. In some embodiments, the one or more thermoplastic polymers are from polyether block amide (PEBA), polyamide 6, polyamide 6/6-6, polyamide 12, or mixtures containing one or more thereof. A polyamide selected from the group consisting of: In some embodiments, the one or more thermoplastic polymers include polyesters or polyester copolymers. In some embodiments, the one or more thermoplastic polymers include polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), poly(L-lactic acid) (PLLA), poly(butylene adipate-co-terephthalate) ( PBAT), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene adipate (PBA), heat a polyester selected from the group consisting of thermoplastic starch (TPS), and mixtures containing one or more thereof. In some embodiments, the one or more thermoplastic polymers are is or includes recycled polymeric material. In some embodiments, the one or more thermoplastic polymers consist of one or more bio-based polymers (eg, bio-based PBAT).

[0012] In some embodiments, the inert gas is mixed with the masterbatch material as a supercritical fluid. In some embodiments, the masterbatch material and supercritical fluid are mixed to form a single phase solution. In other embodiments, the inert gas is mixed with the masterbatch material prior to introducing the masterbatch material into the extruder. In some embodiments, the masterbatch material includes pellets of one or more thermoplastic polymers, and mixing the inert gas with the masterbatch material causes the pellets of one or more thermoplastic polymers to be inert. Including injecting active gas. In some embodiments, injecting the one or more thermoplastic polymer pellets with an inert gas causes the one or more thermoplastic polymer pellets to expand. In some embodiments, introducing the masterbatch material into the extruder includes introducing expanded pellets of one or more thermoplastic polymers into the extruder. In some embodiments, extruding the masterbatch material through an extruder to form a polymer melt includes melting expanded pellets of one or more thermoplastic polymers.

[0013] In some embodiments, a process for manufacturing a flexible foam includes one or more thermoplastic polymers that are recyclable, biodegradable, and/or industrially compostable. providing a plurality of pellets; expanding the pellets of one or more thermoplastic polymers by injecting the pellets with an inert gas; introducing the expanded pellets into an extruder; and the expanded pellets. and extruding the molten expanded pellets through a die using the extruder. In some embodiments, the one or more thermoplastic polymers include polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), poly(L-lactic acid) (PLLA), poly(butylene adipate-co-terephthalate) ( PBAT), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene adipate (PBA), heat is or includes a polymer selected from the group consisting of plastic starch (TPS), and mixtures containing one or more thereof. In some embodiments, the one or more thermoplastic polymers are PBAT , PHA, and/or PHB. In some embodiments, the one or more thermoplastic polymers consist of one or more biobased polymers. In some embodiments, one or the thermoplastic polymers are recyclable polymers. The inert gas may be, for example, nitrogen or carbon dioxide. In some embodiments, the inert gas is at a pressure of 75 bar to 200 bar, such as 90 bar. The inert gas is injected into the pellet at a saturation pressure in the range of ˜150 bar. In some embodiments, the inert gas is injected into the pellet at a temperature in the range of 90° C. to 200° C.

[0014] In some embodiments, foams formed according to the processes described herein are recyclable, biodegradable and/or compostable. In some embodiments, the foam does not include any crosslinking agent. In some embodiments, the foam is free of any crosslinks or crosslinkers that would prevent the foam from being recycled or biodegraded. In further embodiments, foams formed according to the processes described herein can be used in a variety of articles, including, but not limited to, footwear components (e.g., shoe insoles or midsoles), seating components. (e.g., seat cushions), armor components (e.g., pads), vehicle components, bedding components, water sports accessories, or other end products that include foam components.

[0015] The foregoing summary and the following detailed description of the invention will be better understood when read in conjunction with the accompanying drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments that are presently preferred. However, it should be understood that the invention may be embodied in different forms and therefore should not be construed as limited to the embodiments set forth herein. The accompanying drawings may not be drawn to scale.

[0016] FIG. 2 is a flowchart of a process for forming extruded flexible foam, according to some embodiments of the present disclosure. [0017] FIG. 2 illustrates a system for forming extruded flexible foam according to some embodiments of the present disclosure. [0018] FIG. 4 illustrates another system for forming extruded flexible foam, according to a further embodiment of the present disclosure.

[0019] The present disclosure provides, in some embodiments, reusable, biodegradable and/or industrially compostable flexible foams and methods of making the same. Foams according to embodiments of the present disclosure may be closed cell foams. In other embodiments, the foams of the present disclosure may be open cell foams. In various embodiments, the reusable, biodegradable and/or industrially compostable flexible foam is a traditional non-recyclable ethylene vinyl acetate (EVA) foam or thermoplastic polyurethane (TPU) foam. ), but can be formed to contain a high proportion of recycled or bio-based content. Foams made according to embodiments of the present disclosure can be used in a variety of industries and end products, including, but not limited to, footwear components, seating components, armor components, vehicle components, bedding, and water sports accessories. It may be useful in

[0020] As used herein, "biodegradable" generally refers to being capable of being degraded by biological activity, particularly microorganisms. In some embodiments, materials and foams described in this disclosure as biodegradable and/or industrially compostable meet or exceed the requirements set forth in at least one of the following standards: :European Standard EN13432, ASTM D6400, or Australian Standard AS4736. In some embodiments, materials and foams described in this disclosure as biodegradable and/or industrially compostable meet or exceed at least the requirements set forth in European Standard EN13432. In some embodiments, materials and foams described in this disclosure as industrially compostable are configured to exhibit at least 60% biodegradation upon composting within 180 days in a commercial composting unit. (at least 60% of the material must be degraded by biological activity). In some embodiments, materials and foams described in this disclosure as industrially compostable are configured to exhibit at least 90% biodegradation upon composting within 180 days in a commercial composting unit. has been done.

[0021] In some embodiments, the term "reusable" generally refers to collection, separation, or otherwise recovered from a waste stream for reuse or use in manufacturing or assembling another item. Sometimes refers to the ability of a material or product to be used. In some embodiments, polymers and foams described in this disclosure as recyclable are recovered by, for example, mechanical recycling, chemical recycling, and/or biological or organic recycling. Refers to the ability of component materials. In some embodiments, polymers and foams described in this disclosure as recyclable are components of component materials that are recovered using standard plastic recycling methods as set forth in ISO 15270:2008, for example. Say ability. In some embodiments, the recycled materials, foams and/or products described herein meet Textile Exchange Recycling Labeling Standard 2.0 (RCS, July 1, 2017) and/or or may be manufactured in accordance with the requirements set out in the Textile Exchange Global Recycling Standard 4.0 (GRS, July 1, 2017).

[0022] In some embodiments, a process for forming an extruded flexible foam according to the present disclosure generally includes introducing polymer pellets into an extruder and extruding them to form a polymer melt. The method includes melting the polymer pellets in a machine and extruding the polymer melt through a die to form an extrudate. In some embodiments, a blowing agent is introduced into the extruder and mixed with the polymer melt. In some embodiments, the blowing agent is introduced as a supercritical fluid to form a single phase solution with the polymer melt. In other embodiments, the polymer pellets are saturated with a blowing agent prior to introducing the polymer pellets into the extruder. As further described herein, the polymer pellets are preferably comprised of one or more thermoplastic polymers that are recyclable, biodegradable and/or industrially compostable. In some embodiments, the polymer pellets are comprised of bio-based thermoplastic polymers. In some embodiments, the polymer pellets are formed from recycled plastic material.

[0023] FIG. 1 is a flowchart of a process 100 for forming extruded flexible foam, according to some exemplary embodiments of the present disclosure. At step 102, in some embodiments, process 100 includes providing a masterbatch of one or more preselected materials. The masterbatch, in some embodiments, consists of thermoplastic polymeric material in the form of pellets, granules, etc. As mentioned above, the one or more preselected materials preferably include one or more recyclable, biodegradable and/or industrially compostable materials, according to some embodiments. It is a thermoplastic polymer. In some embodiments, one or more preselected materials are obtained from recycled plastic waste materials. In some embodiments, the masterbatch consists entirely of one or more preselected biodegradable materials (eg, biodegradable thermoplastic polymers). In some embodiments, the masterbatch consists entirely of one or more preselected recyclable materials (eg, recyclable thermoplastic polymers).

[0024] In step 104 of process 100, an inert gas is mixed with the masterbatch. In some embodiments, an inert gas (eg, blowing agent) is mixed with the masterbatch in one or more extruders. The inert gas may be mixed with the masterbatch as a supercritical fluid in some embodiments. In some embodiments, the masterbatch is melted to form a single phase solution with the supercritical fluid. In other embodiments, the masterbatch is saturated with an inert gas (eg, a blowing agent) before introducing the masterbatch into one or more extruders.

[0025] In some embodiments, saturating the pellets of the masterbatch with an inert gas injects a portion of the gas into the pellets, causing the pellets to at least partially expand. In some embodiments, saturating the masterbatch with an inert gas forms swollen (expanded) or at least partially swollen polymer pellets, which are then subjected to extrusion (e.g., ) can be melted. In some embodiments, the expanded polymer pellets have a size (eg, in their widest dimension) of 4 mm to 10 mm. In some embodiments, the expanded polymer pellets have a bulk density of about 100 kg/m ³ to about 200 kg/m ³ . In some embodiments, the polymer pellets have an expansion ratio ranging from about 1.5 to about 4.5. In some embodiments, the inert gas saturation pressure can range from 75 bar to 200 bar, such as from 90 bar to 150 bar. In some embodiments, the inert gas saturation temperature depends on the dropping point and melting temperature of the particular biodegradable, industrially compostable, and/or recycled and/or recyclable polymer. The temperature can range from 90°C to 200°C. Additionally, in some embodiments, the average pore size and cell density of the foam can be controlled to some extent by adjusting the saturation pressure. In some embodiments, high inert gas saturation pressures are preferred to obtain small average pore sizes and high cell density. In further embodiments, the polymer may optionally be pre-dried and dehumidified before foaming. In some embodiments, for example, pre-drying conditions range from 65 to 85°C for 4 to 6 hours at a dew point of -40°C and a relative humidity of less than 0.05%.

[0026] In step 106, the masterbatch mixed with gas forms a polymer melt that is extruded through one or more extruders. The extruder or extruders may be, for example, a screw extruder having one or more extrusion screws for compressing and conveying the polymer melt. In step 108, the polymer melt is extruded into a sheet of microcellular foam. In some embodiments, the polymer melt is extruded through a die configured to form an extrudate. In some embodiments, gases mixed within the polymer melt are expanded as the polymer melt is extruded through a die, resulting in a flexible foam. In further embodiments, the flexible foam is then cut and/or shaped (eg, via compression molding) into any desired configuration.

[0027] The subject matter of the present invention will now be described in more detail below, where representative embodiments are described. However, the present subject matter may be embodied in different forms and should not be construed as limited to the particular embodiments set forth herein. Rather, these embodiments are provided to explain and enable those skilled in the art.

[0028]Thermoplastic polymer
[0029] In some embodiments, producing microcellular extruded foam from recycled and/or recyclable thermoplastic polymers, or alternatively, bio-based thermoplastic polymers, is suitable It starts with choosing a high-performance polymer. Suitable thermoplastic polymers that may be utilized in accordance with embodiments of the present disclosure should preferably include the following properties: produce a low density foam, have a medium melt flow rate, have a high elongation and is 100% recyclable and/or 100% industrially compostable. In some non-limiting examples, suitable thermoplastic polymers include foams having a density of 0.15 g/cc to 0.35 g/cc, preferably 0.20 g/cc to 0.25 g/cc. Manufacture. In some non-limiting examples, suitable thermoplastic polymers have melt flow rates ranging from 5 g/10 min to 30 g/10 min, preferably from 10 g/10 min to 20 g/10 min. In other examples, the melt flow rate may range from 7 g/10 min to 15 g/10 min. In some non-limiting examples, suitable thermoplastic polymers produce foam elongations in the range of 150% to 800%, preferably 250% to 450%. In some embodiments, the thermoplastic polymer may be provided in the form of solid pellets that are sized and configured to be fed to an extruder. The plurality of pellets of polymeric material fed to the extruder may also be referred to herein as a "masterbatch."

[0030] In some embodiments, the thermoplastic polymer used to make the reusable, biodegradable, and/or industrially compostable flexible foams of the present disclosure may be any A number of polyamides or polyamide copolymers can be selected. Non-limiting examples of suitable polyamide polymers include polyether block amide (PEBA), polyamide 6, polyamide 6/6-6, polyamide 12, and mixtures containing one or more thereof. A non-limiting example of a suitable recycled and/or reusable polymer is PEBA manufactured by Nylon Corporation of America of Manchester, New Hampshire.

[0031] In some embodiments, the thermoplastic polymer used to make the reusable, biodegradable, and/or industrially compostable flexible foams of the present disclosure may be any Polyesters or polyester copolymers can be selected from a number of polyesters or polyester copolymers, preferably polyesters of biological origin. Non-limiting examples of suitable polyester polymers include polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), poly(L-lactic acid) (PLLA), poly(butylene adipate-co-terephthalate) (PBAT), Caprolactone (PCL), Polyhydroxyalkanoate (PHA), Polyhydroxybutyrate (PHB), Polybutylene Succinate (PBS), Polybutylene Succinate Adipate (PBSA), Polybutylene Adipate (PBA), Thermoplastic Starch (TPS) ), and mixtures containing one or more thereof. In some embodiments, the thermoplastic polymer selected for the reusable, biodegradable, and/or industrially compostable flexible foams of the present disclosure comprises or consists entirely of PBAT. Consists of PBAT. In some embodiments, the thermoplastic polymer selected for the reusable, biodegradable, and/or industrially compostable flexible foams of the present disclosure comprises or is completely PHA-based. Consists of PHA.

[0032] In some embodiments, recycled raw materials are used to make suitable recyclable polymers or polymer blends of the present disclosure. The goal of some embodiments is to use recycled polymer feedstock whenever possible. An example of using recycled raw materials is post-industrial polyamide carpet fiber, collected marine plastic fishing nets, or other plastic waste that is collected, sorted, melted, and reprocessed, according to some embodiments. It is the use of physical materials. In some such embodiments, the collected waste material can be reprocessed into virgin quality polyamide precursors (eg, caprolactam). Typical caprolactam obtained from post-industrial carpet fibers and used fishing nets is available from Aquafil USA Inc., Cartersville, Georgia. Econyl manufactured by. The aforementioned thermoplastic polymer resins have exhibited advantageous technical properties in forming optimal microcellular flexible foam structures according to embodiments of the present disclosure. Some of these technical properties include exceptional degradability, excellent elongation, tensile strength, and compression set, among other advantages.

[0033] Additionally, in some embodiments, biologically derived polymers are used to make the flexible foams of the present disclosure. In some embodiments, the term "biologically derived" or "biopolymer" or "bioplastic" as used herein refers to polymers derived from biological sources (as opposed to, e.g., petroleum-based sources); or may be used to refer to polymers formed from precursor materials (eg, monomers) derived from biological sources. In some such embodiments, the biological source may be of renewable plant origin. One non-limiting example of a suitable biopolymer for use in this disclosure is bio-based PBAT manufactured by Novamont SpA of Novara, Italy. This bio-based PBAT is biodegradable and industrially compostable, and the polymer precursors, namely azelaic acid and bio-based bio-butanediol (bio-BDO), are the primary bio-based properties of the polymer. form. This bio-derived PBAT exhibits overall advantageous technical properties in forming optimal microcellular flexible foam structures according to embodiments of the present disclosure. Some of the improved technical properties include exceptional degradability, superior elongation, tensile strength, and compression set, among other benefits. In addition to plants, in some embodiments the biological origin of the "biologically derived" or "biopolymer" or "bioplastic" material may be, for example, microorganisms (e.g., bacteria), algae, animals (e.g., fats/lipids) and/or insects.

[0034] In some embodiments, mixtures of two or more thermoplastic polymers can be utilized. In some embodiments, a mixture of two or more thermoplastic polymers can provide a combination of properties not found in a single polymer. There are several ways to successfully mix polymers. One such method uses a twin-screw extruder to melt two or more polymer resins, then extrude the molten polymer resin mixture into strands, which are cooled to form a masterbatch. is fed into a pelletizer to produce an array of pelletized pieces called . Another method of polymer mixing is to use compatibilizers to combine the different polymers in a polymer mixture. This method may also use a twin screw extruder or the like to melt the compatibilizer and two or more polymers to form a mixture.

[0035] Additives
[0036] In some embodiments, one or more additives may be selectively added to the polymer formulation depending on the application. The one or more additives can include, for example, one or more fillers, nucleating agents and/or colorants. In some embodiments, one or more additives may be included to adjust the physical and/or chemical properties of the resulting foam. Preferably, in some embodiments, the one or more additives include or consist of recyclable and/or compostable materials. In some embodiments, one or more biodegradable and/or recyclable binders are optionally included to help melt the expanded pellets. In some embodiments, one or more additives may be added to the polymer (eg, mixed with the masterbatch) prior to extrusion. In some embodiments, one or more additives may additionally or alternatively be added to the extruder and mixed with the polymer in the extruder (e.g., via side feed into the extruder). hand).

[0037] In some embodiments, one or more fillers may be optionally added to the polymer to reduce part cost. For example, in some embodiments, one or more fillers have a lower cost per weight than the polymeric material and are used to add physical bulk and/or improved specific performance to the product. It's okay to be. In some non-limiting examples, one or more fillers, if included, may be added in a range of 1% to 30% by weight. The filler or fillers may include, for example, precipitated calcium carbonate, ooliform aragonite, starch, biomass, and the like. In some embodiments, the materials for the one or more fillers are selected such that the flexible foam and/or the final product remains reusable and/or compostable.

[0038] Nucleating agents, such as fine lamellar talc or high aspect ratio ooliform aragonite, may be included in some embodiments. Nucleating agents, in some embodiments, improve results by preventing cell coalescence (e.g., bubble merging), reducing bulk density, and improving rebound resilience, among other advantageously enhanced properties. The main properties of the resulting flexible foam can be significantly improved. In some such embodiments, the nucleating material improves foaming by increasing the amount of individual cells in the foam material. Non-limiting examples of nucleating agents for use in making flexible foams are available from Imerys Talc America Inc., Houston, Texas. and high aspect ratio ooliform aragonite sold as OceanCal® by Calcean Minerals & Materials LLC of Gadsden, Alabama. In some non-limiting examples, one or more nucleating agents, if included, may be included in a range of 0.1% to 10% by weight ratio.

[0039] In further embodiments, one or more additives configured to accelerate and/or improve biodegradation of the finished foam product may be included. In one example, oligomeric poly(aspartic acid-co-lactide) (PAL) is selectively used to accelerate biodegradation and for certain end market uses, as may be appropriate in some instances. May be mixed into a masterbatch.

[0040] In some embodiments, one or more colorants may be selectively included to change the color of the resulting flexible foam. For example, various colorants such as dyes or pigments may optionally be included in the polymer formulations of the present invention. Some non-limiting examples include pigments prepared for use with certain types of thermoplastic polymers, such as those manufactured by Treffert GmBH & Co., Doyle, Bingen am Rhein. Pigments provided by KG or Holland Colors Americas Inc., Richmond, Indiana. It is provided by. In some non-limiting examples, one or more colorants, if included, may be added in a range of 0.1% to 5% by weight ratio.

[0041] Foaming agent
[0042] To make foams according to some processes of this disclosure, the polymer formulation is mixed with a blowing agent. A widely known blowing agent used in conventional manufacturing processes is azodicarbonamide (ADA). ADA is typically pre-impregnated into conventional thermoplastic masterbatch resins for use in conventional injection molding foam processes. However, ADA is not considered environmentally friendly and is a suspected carcinogen for human health. Additionally, conventional foaming processes using ADA typically produce foams that are crosslinked during the manufacturing process and are therefore not recyclable or compostable. Therefore, in preferred embodiments, the processes of the present disclosure do not use ADA.

[0043] In some embodiments, an inert gas is used as a blowing agent for the foaming process of the present disclosure. In some embodiments, the blowing agent used in embodiments of the present disclosure is either nitrogen gas ( _N2 ) or carbon dioxide ( _CO2 ). In some embodiments, the blowing agent is mixed with the polymeric material as a supercritical fluid (SCF). In some embodiments, the SCF and polymeric material form a single phase solution. In some embodiments, the foaming process of the present disclosure includes passing a single phase solution of polymer and supercritical fluid (SCF) through an extruder die to form a continuous format extrudate. In some embodiments, the extrudate is annular. In some embodiments, the extrudate is formed into a flat sheet. Other shapes are possible according to other embodiments. In some embodiments, homogeneous cell nucleation occurs when a single phase solution of polymer and supercritical fluid (SCF) passes through an extruder die. In some embodiments, as the solution exits the extruder die, the pressure drops, which then causes the SCF to exit the solution and form the cell core. The cells then grow until the material expands, expending the expansion capacity of the SCF, thereby stabilizing the resulting foam. As further described herein, the process according to some embodiments is performed in an extrusion machine modified to allow metering, evacuation and mixing of inert SCF into the polymer to form a single phase solution. It may be done.

[0044] The difference in effectiveness of nitrogen and carbon dioxide as blowing agents arises from their behavior in polymer melts. Carbon dioxide, which becomes an SCF at temperatures and pressures above the critical point (about 31° C. and about 73 bar), is 4-5 times more soluble in polymers than nitrogen, which becomes a supercritical fluid at about −147° C. and about 34 bar. For example, the saturation point in unfilled polymers is about 1.5 to 2 weight percent of nitrogen, depending on temperature and pressure conditions, while the saturation level of carbon dioxide is closer to 8 weight percent. Carbon dioxide also exhibits greater mobility in the polymer, allowing it to move further into existing gas bubbles than nitrogen. From a cell nucleation perspective, higher solubility and mobility means fewer cells are nucleated, and those that do tend to be larger.

[0045] However, solubility is an advantage according to some embodiments when the goal is viscosity reduction. In some embodiments, lower viscosity may be advantageous due to lower part weight. In some embodiments, SCF dissolved in the polymer acts as a plasticizer and reduces the viscosity of the polymer. Viscosity reduction is, in part, a function of the amount of SCF added to the polymer, and since carbon dioxide has a higher solubility limit than nitrogen, the ability to reduce viscosity is greater with carbon dioxide.

[0046] Carbon dioxide is also preferred as a blowing agent in some embodiments when the amount of nitrogen required to manufacture the part is low so that the part cannot be processed consistently. In some embodiments, if carbon dioxide has a higher solubility in the polymer than nitrogen, low levels of carbon dioxide, 0.05 percent, compared to very low levels of nitrogen, less than 0.05 percent. Sometimes it is easier to use 15 or 0.2 percent. This mainly occurs with flexible materials and parts with thick cross-sections.

[0047] In some alternative embodiments, one or more blowing agents are used to pre-expand pre-foamed pellets of polymeric material. In some embodiments, the blowing agent is an inert gas. In some such embodiments, the blowing agent can be either nitrogen or carbon dioxide. In some embodiments, pre-expansion involves injecting a gas (eg, nitrogen or carbon dioxide) into the polymer pellets, thereby forcing individual expansion to form pre-expanded, expanded pellets. In some embodiments, these pre-foamed pellets are then extruded into continuous sheets of varying thickness and length to meet any need. The finished fused sheet of pellets is the result of each individual pre-foamed pellet being fused into multiple foamed and fused pellets. The finished homogeneous sheet is then ready for die cutting and forming by conventional means such as those known in the art.

[0048] Extrusion system
[0049] According to some aspects, the present disclosure provides a system for producing a flexible foam that is reusable, biodegradable, and/or industrially compostable. In various embodiments, the system may include one or more of the following components: at least one extruder configured to melt and convey the polymeric material (e.g., a hopper configured to introduce the material into the extruder (in the form of pellets), and a die for shaping the material extruded by the extruder. In some embodiments, the aforementioned components may be combined into a single device. In some embodiments, systems according to the present disclosure further include a gas source configured to provide a blowing agent (eg, nitrogen or carbon dioxide) for mixing with the polymeric material. In some embodiments, the system further controls one or more of various process parameters of the extrusion system, such as, but not limited to, temperature, pressure, polymer feed rate, gas dosing, or extrusion rate. including a control system configured to control.

[0050] In some embodiments, at least one extruder may be a screw extruder. In some such embodiments, the screw extruder includes a barrel and at least one screw disposed within the barrel and configured to rotate within the barrel. In some embodiments, at least one screw is configured to compress, melt, and convey polymeric material introduced into the extruder. In some embodiments, a hopper may be included to feed a polymer masterbatch (eg, pelletized polymer material) into the barrel of the extruder. In some embodiments, the polymer masterbatch may be gravity fed from the hopper through the throat of the hopper and into the barrel and screw assembly of the extruder.

[0051] In some embodiments, at least one screw may be driven by one or more motors. In some embodiments, the screw extruder is a multi-screw extruder having two or more rotating screws. In some such embodiments, the screw extruder may be a twin screw extruder having a pair of parallel screws that are intermeshed with each other. In further embodiments, the screw may be a reciprocating screw. A reciprocating screw may include three zones: a feed zone, a compression (or transition) zone, and a metering zone. In some embodiments, the system includes at least two extruders. In some embodiments, the system includes a first melt extruder that feeds material to a second cooling extruder.

[0052] In some embodiments, there may be a nozzle connecting the extruder barrel to the die and forming a seal between the barrel and the die. In some embodiments, the temperature of the nozzle may be set at or slightly below the melting temperature of the polymeric material. In some embodiments, the die includes a sprue bushing and the nozzle is connected to the sprue bushing. In some embodiments, an evacuation system may also be included. The exhaust system, in some embodiments, provides a path for the molten polymer from the nozzle to the die and may generally include sprues, cold slug wells, main runners, branch runners, gates, and the like. In some embodiments, when the barrel is in the fully forward processing position, the radius of the nozzle may fit and seal a concave radius in a sprue bushing with a locating ring. During barrel purging (cleaning), the barrel may be backed out of the sprue, allowing the purge compound to free fall from the nozzle.

[0053] In a further embodiment, the system additionally receives a gas (e.g., nitrogen or carbon dioxide) and directs the received gas into the barrel of the extruder under conditions for producing a supercritical fluid upon said introduction. A supercritical fluid (SCF) administration system configured to introduce the supercritical fluid (SCF) may be included. In some embodiments, a supercritical fluid administration system may be configured to alter the pressure and/or temperature of a received gas above the critical point of the gas. In some embodiments, for example, the SCF dosing system includes a gas (e.g., nitrogen or carbon dioxide) supply, an air compressor, an SCF metering and control device, an SCF injector, and front and back check valves. good. In some embodiments, the supercritical fluid is mixed with the thermoplastic polymer within the barrel of the extruder. In some embodiments, the supercritical fluid and thermoplastic polymer form a single phase solution within the barrel of the extruder. In some embodiments, the production of a single-phase solution in which the SCF is completely dissolved and uniformly dispersed in the molten polymer occurs within an extruder barrel under carefully controlled process conditions. In some embodiments, the SCF should be a precisely measured mass flow rate into the polymer for a fixed amount of time, during which specific conditions of temperature, pressure, and shear are applied. Must be established within the barrel. In some embodiments, back pressure, screw speed and barrel temperature control, and the SCF dosing system all play a role in establishing process conditions that produce a single phase solution.

[0054] In some embodiments, the process setup procedure revolves around establishing controlled SCF dosing into the extruder barrel under screw speed, temperature, and pressure conditions that result in a single-phase solution. . In some embodiments, one or more of the following system parameters may be adjusted to ensure that the basic conditions for SCF administration are met:
1) SCF Saturation Pressure: In some embodiments, the effects of inert gas saturation pressure and saturation temperature play a major role in the expansion ratio of the foam. In some non-limiting examples, the saturation pressure may range from 75 bar to 200 bar, preferably from 90 bar to 150 bar. The inert gas saturation temperature can range from 90°C to It can be in the range of 200°C. Additionally, the average pore size and cell density of the foam can be controlled to some extent by adjusting the saturation pressure (the pressure of inert gas saturation on the selected polymer). High inert gas saturation pressures are preferred in some embodiments to obtain small average pore sizes and high cell density. The effects of inert gas saturation pressure and saturation temperature play a major role in the expansion ratio of the foam.
2) SCF Injector Open Position: This set point sets the screw position at which SCF administration is open. The position should be set so that the pressure in the barrel during screw recovery stabilizes before the start of dosing. As a non-limiting example, the open position can range from 7.62 mm (0.3 inches) to 10.16 mm (0.4 inches).
3) Percent SCF: This controls the actual mass of SCF administered. A non-limiting example of a SCF percentage can range from 0.45% to 0.75%, more preferably 0.5%.
4) Dosing optimization: This is achieved by maximizing the dosing time and minimizing the flow rate (differential pressure between pre-metering pressure and discharge pressure). A non-limiting example of an administration time is 1-2 seconds, more preferably 1.7 seconds. In some embodiments, a single polymer melt is nucleated within a die and released as a single polymer melt stream at the exit of the die, such that the opening time is preferably only a fraction of a second.

[0055] In some embodiments, once the single-phase solution is produced, the extruder maintains the solution under pressure until the beginning of extrusion. In some embodiments, the extruder does so through the combined efforts of pressure regulator valves and melt pump controls. In some embodiments, a pressure regulator valve prevents pressure reduction and premature foaming into the die element. In further embodiments, active or passive screw position control may be utilized to prevent decompression due to backward movement of the screw. In some such embodiments, during active screw position control, the position of the screw is continuously monitored and the pressure applied behind the screw is adjusted or kept constant to maintain the position setpoint. pressure is maintained behind the screw. In passive position control, oil may be used to regulate back pressure and prevent spillage into the tank at the end of screw recovery. This residual oil keeps the screw from moving backwards due to the pressure of the single phase solution.

[0056] In some embodiments, the systems of the present disclosure further include one or more temperature sensors configured to monitor and/or control the temperature within the barrel or other components of the system. That's fine. In some embodiments, the system may include one or more pressure sensors configured to monitor and/or control pressure within the barrel or other components of the system. Additionally, a control unit having one or more microprocessors may be included, the control unit controlling one or more of the extruder and the supercritical gas dosing system according to one or more system parameters. configured to control. In some embodiments, the control system may be configured to provide consistency and reproducibility in extruder operation. In some embodiments, the control system monitors and controls process parameters including temperature, pressure, SCF dosing, injection rate, screw speed and position, and hydraulic position. Control systems can range from simple relay on/off controls to highly sophisticated microprocessor-based closed loop controls.

[0057] In some embodiments, the system and/or any subsystem thereof may include one or more sensors, such as a temperature sensor, a pressure sensor, an accelerometer, a gyroscope, and an orientation sensor. In some embodiments, the one or more sensors are configured to be positioned within the extruder, die, etc., in communication with one or more of the other components of the extrusion system. There is. In various embodiments, one or more sensors may be smart sensors and may include a communication module configured to connect to a network. In some embodiments, the communication module may be further configured to perform wireless communications. In some embodiments, the system and/or any of its various parts are configured such that the communication module supports one or more wireless communication protocols, including WIFI, Bluetooth, low energy Bluetooth, and 3G, 4G and 5G cellular communications. The communication module may include a communication module that may be coupled to one or more of a control system, an SCF administration system, and a gas counterpressure control unit, such as configured to perform a control system.

[0058] FIG. 2 depicts a system 200 for manufacturing flexible foam according to one non-limiting example. In some embodiments, in a first stage, system 200 includes a pressure vessel 202 configured to contain pellets of masterbatch 204. The pellets may be comprised of any one or more of the non-limiting examples of thermoplastic polymeric materials mentioned above. For example, the pellets may consist entirely of one or more recyclable thermoplastic polymers, or may consist entirely of one or more biodegradable thermoplastic polymers (e.g., one or more biopolymers). It may consist of In some embodiments, the pellets of masterbatch 204 may be injected or saturated with an inert gas (eg, carbon dioxide or nitrogen) within pressure vessel 202.

[0059] In some embodiments, the effects of inert gas saturation pressure (eg, in pressure vessel 202) and saturation temperature play a major role in the expansion ratio of the foam. In some embodiments, the saturation pressure may range from 75 bar to 200 bar, preferably from 90 bar to 150 bar. Inert gas saturation temperatures range from 90°C to 200°C, depending on the dropping point and melting temperature of the particular biodegradable, industrially compostable, and/or recycled and/or recyclable polymer. can be in the range of Additionally, the average pore size and cell density of the foam can be controlled to some extent by adjusting the saturation pressure, ie, the pressure of inert gas saturation into the selected polymer. High inert gas saturation pressure is ideal to obtain small average pore size and high cell density.

[0060] In some embodiments, in a second stage following saturation with an inert gas, the pellets of masterbatch 204 are transferred to a hopper 206 that is configured to feed the pellets to an extruder 208. The pellets may be in an expanded state after saturation with an inert gas. In some embodiments, extruder 208 includes one or more extruder screws 210 contained within and configured to rotate within barrel 212. Rotation of one or more extrusion screws 210 may be driven by a motor 214, for example. In some embodiments, one or more extrusion screws 210 are configured to convey, compress, and melt together the saturated pellets of masterbatch 204 as the pellets are extruded through extruder 208; Form a polymer melt. In some embodiments, one or more biodegradable and/or recyclable binders are optionally included to help melt the pellets.

[0061] In some embodiments, the polymer melt is extruded through die 216 by extruder 208. Die 216 may be positioned at the end of extruder 208 in some embodiments and is configured to shape the polymer melt as it passes through die 216. In some embodiments, the temperature of die 216 is set at or slightly below the melting temperature of the polymeric material. In some embodiments, the polymer melt is forced through die 216 and passes through calibrator 218. In some embodiments, calibrator 218 is configured to cool the extrudate following extrusion through the die. In some embodiments, calibrator 218 is connected to a temperature control unit 220 (eg, a Thermolator® temperature control unit). In some embodiments, temperature control unit 220 is configured to control the temperature of calibrator 218. In some embodiments, calibrator 218 and/or temperature control unit 220 are configured to cool the extrudate sufficiently as it passes through calibrator 218 to solidify the extrudate. .

[0062] In a further embodiment, calibrator 218 is connected to vacuum system 222. In some embodiments, vacuum system 222 is configured to create a low pressure zone. As the polymer melt exits the die 216 and is exposed to a low pressure zone, the gases introduced into the polymer melt expand and form an extruded foam 226. In a further embodiment, a pulling system 224 is included to convey extruded foam 226 from die 216. Tensioning system 224 may include, for example, one or more rollers configured to receive extruded foam 226. In some embodiments, the rollers of the pulling system help shape the extruded foam 226 (eg, into a flat sheet).

[0063] FIG. 3 depicts a system 300 for manufacturing flexible foam according to another non-limiting example. In some embodiments, system 300 includes a hopper 302 configured to feed pellets of masterbatch 304 to a first extruder 306. The pellets may be comprised of any of the non-limiting thermoplastic polymeric materials mentioned above. In some embodiments, first extruder 306 is a melt extruder. In some embodiments, first extruder 306 includes one or more extruder screws 308 that are housed within barrel 310 and configured to rotate within barrel 310. Rotation of the extrusion screw or screws 308 may be driven, for example, by a first motor 312 connected to the extrusion screw 308 by a system of gears 314. In some embodiments, one or more extrusion screws 308 are configured to convey, compress, and melt pellets of masterbatch 304 as the pellets are extruded through first extruder 306 to Form a melt.

[0064] The system 300, in some embodiments, includes a supercritical fluid (SCF) dosing system 316 configured to supply an inert gas into the first extruder 306 to be mixed with the polymer melt. including. In some such embodiments, the SCF dosing system 316 includes, for example, a supply (e.g., tank) 318 of an inert gas (e.g., nitrogen or carbon dioxide), a pump controller 320, a flow of inert gas, etc. It includes one or more of valves 322 , 324 for controlling, and injection line 316 for injecting inert gas into first extruder 306 . In some embodiments, the SCF dosing system 316 is configured to introduce an inert gas as a supercritical fluid into the first extruder 306. In some such embodiments, the SCF dosing system 316 is configured to inject the inert gas into the first extruder at a pressure and temperature above the critical point of the gas. For example, in some embodiments, SCF administration system 316 is configured to introduce supercritical fluid at a pressure in the range of about 150 bar to about 300 bar and a temperature of about 150°C to about 350°C. In some embodiments, the SCF administration system 316 is configured to introduce supercritical fluid at a pressure in the range of about 90 bar to about 150 bar and a temperature of about 90°C to about 200°C. In some embodiments, the pressure and temperature within the first extruder 306 are sufficient to maintain the inert gas in a supercritical state.

[0065] In some embodiments, the supercritical fluid and polymer melt are mixed within the first extruder 306 to form a single phase solution. In some embodiments, a single phase solution is extruded from first extruder 306 via tube 328 to second extruder 330. In some embodiments, second extruder 330 is a chilled extruder. In some embodiments, the use of second extruder 330 helps avoid foam cell collapse and shrinkage. In further embodiments, the use of a second extruder 330 helps produce a smooth and homogeneous foam structure. In some embodiments, the second extruder 330 includes one or more extruder screws 332 that are housed within a second barrel 334 and configured to rotate within the second barrel 334. Rotation of the extrusion screw or screws 332 may be driven, for example, by a second motor 336 connected to the extrusion screw 332 by a second system of gears 338. In some embodiments, one or more extrusion screws 332 are internally cooled (eg, via water, oil, or other coolant). In some such embodiments, cooling the one or more extrusion screws 332 may prevent polymeric material extruded through the second extruder 330 from sticking to the one or more extrusion screws 332. .

[0066] In some embodiments, second extruder 330 is configured to convey and extrude the polymer melt through die 340. Die 340 is configured, in some embodiments, to shape the polymer melt as it passes through die 340. In some embodiments, system 300 includes a mixer 342 disposed between second extruder 330 and die 340. In a further embodiment, system 300 includes a heat exchanger 344 disposed between second extruder 330 and die 340. In a further embodiment, system 300 includes a melt pump 346 disposed between second extruder 330 and die 340. In some embodiments, melt pump 346 is configured to precisely control the output of die 340. In some such embodiments, melt pump 346 includes a suction side that receives extruded material from second extruder 330 and a discharge side that outputs extruded material to die 340. In some embodiments, the extruded material passes through mixer 342 from second extruder 330 to melt pump 346. In some embodiments, melt pump 346 is configured to output extruded material to die 340 at a more consistent pressure and volume. In some embodiments, heat exchanger 344 is configured to help regulate the temperature of second extruder 330, melt pump 346, and/or die 340. In some embodiments, as the polymer melt exits die 340, the gas introduced into the polymer melt expands and forms extruded foam 350. In some embodiments, a pulling system 348 may be included to convey extruded foam 350 from die 340.

[0067] In some embodiments, system 300 may further include one or more sensors 352 coupled to various components of the system. One or more sensors 352 may include, for example, pressure sensors, temperature sensors, etc. configured to measure various operating parameters of the component. One or more sensors 352 may be coupled to one or more of first extruder 306, second extruder 330, and die 340, for example. In some embodiments, one or more sensors 352 may be further configured to communicate (e.g., wirelessly) with a control system (not shown), which itself may be configured to communicate with one or more sensors 352. The system 300 is configured to control operation of the components of the system 300 in response to parameters detected by the sensor 352 of the system 300 . For example, the control system in some embodiments uses feedback from one or more sensors 352 to operate and/or maintain certain components of system 300 at a predetermined range of temperatures and/or pressures. may depend on. Extruder speed, temperature control system, and/or other components may be adjusted by the control system.

[0068] As described herein, foams made according to embodiments of the present disclosure can be used in a variety of industrial and end products, including, but not limited to, footwear components (e.g., shoes). Insoles or midsoles), seating components, armor components, vehicle components, bedding materials, and water sports accessories. In some embodiments, the extruded foams of the present disclosure may be formed with various predetermined dimensions (eg, thickness, length, width) depending on the intended use. In further embodiments, the extruded foam may subsequently be cut or shaped (eg, via compression molding) to form foam pieces useful for forming the final product. For example, sheets of biodegradable and/or reusable foam formed according to embodiments of the present disclosure may be die cut into usable pieces that may be referred to as "blockers." The blocker may then be compression molded, for example, to form a shaped footwear midsole for use in constructing a shoe or other footwear.

[0069] Because the foam according to some embodiments is formed from recycled, recyclable, biodegradable, and/or compostable materials without crosslinking, the foam is Provides an environmentally friendly alternative to foam materials (e.g. EVA or TPU foam). At the end of the foam's pot life, the foam can be selectively biodegraded or composted in the case of biodegradable foams, or can be selectively biodegraded or composted in the case of reusable foams (e.g. can be recycled and reprocessed (into new foam). In some embodiments, the foam can be broken down again into usable precursor components (eg, monomers) due to the lack of crosslinkers or other interfering chemical additives.

[0070] It should be understood that various changes, substitutions, and modifications can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. It should also be clear that individual elements identified herein as belonging to a particular embodiment may be included in other embodiments of the invention. Furthermore, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure herein, any now existing or later embodiments that perform substantially the same function or achieve substantially the same results as corresponding embodiments described herein. Any process, machine, manufacture, composition of matter, means, method or steps developed may be utilized in accordance with the present invention.

Claims (35)

introducing into the extruder a masterbatch material consisting essentially of one or more recycled, recyclable, biodegradable and/or compostable thermoplastic polymers;
mixing an inert gas with the masterbatch material;
extruding the masterbatch material through the extruder to form a polymer melt;
passing the polymer melt through a die to form an extrudate;
and expanding the extrudate into a foam.
Process for producing flexible foam. the inert gas is carbon dioxide;
A process according to claim 1. the inert gas is nitrogen,
A process according to claim 1. the one or more thermoplastic polymers include polyamides or polyamide copolymers;
A process according to any one of claims 1 to 3. The one or more thermoplastic polymers are
polyether block amide (PEBA),
polyamide 6,
polyamide 6/6-6,
polyamide 12,
mixtures containing one or more of them;
comprising a polyamide selected from the group consisting of
A process according to any one of claims 1 to 4. the one or more thermoplastic polymers include polyester or polyester copolymers;
A process according to any one of claims 1 to 3. The one or more thermoplastic polymers are
polybutylene adipate terephthalate (PBAT),
polylactic acid (PLA),
poly(L-lactic acid) (PLLA),
poly(butylene adipate-co-terephthalate) (PBAT),
polycaprolactone (PCL),
polyhydroxyalkanoate (PHA),
polyhydroxybutyrate (PHB),
polybutylene succinate (PBS),
polybutylene succinate adipate (PBSA),
polybutylene adipate (PBA),
thermoplastic starch (TPS),
mixtures containing one or more of them;
comprising a polymer selected from the group consisting of
A process according to any one of claims 1 to 3 and 6. the one or more thermoplastic polymers include one or more recycled polymeric materials;
A process according to any one of claims 1 to 7. the one or more thermoplastic polymers consisting of one or more bio-based polymers;
A process according to any one of claims 1 to 7. the one or more bio-based polymers include bio-based PBAT;
Process according to claim 9. the inert gas is mixed with the masterbatch material as a supercritical fluid;
A process according to any one of claims 1 to 10. the masterbatch material and the supercritical fluid are mixed to form a single phase solution;
12. Process according to claim 11. the inert gas is mixed with the masterbatch material prior to introducing the masterbatch material into the extruder;
A process according to any one of claims 1 to 10. the masterbatch material comprises pellets of one or more thermoplastic polymers;
mixing the inert gas with the masterbatch material includes injecting the inert gas into the pellets of the one or more thermoplastic polymers;
14. Process according to claim 13. injecting the inert gas into the pellets of the one or more thermoplastic polymers expands the pellets of the one or more thermoplastic polymers;
15. Process according to claim 14. introducing the masterbatch material into the extruder includes introducing the expanded pellets of the one or more thermoplastic polymers into the extruder;
16. Process according to claim 15. extruding the masterbatch material through the extruder to form a polymer melt includes melting the expanded pellets of the one or more thermoplastic polymers;
17. Process according to claim 16. 18. A foam produced by a process according to any one of claims 1 to 17. the foam is reusable, biodegradable and/or compostable;
The foam according to claim 18. the foam does not contain any crosslinking agent;
The foam according to claim 18 or 19. An article comprising a foam made according to any one of claims 1 to 17. the article is a footwear component, a seating component, an armor component, a vehicle component, bedding or a water sports accessory;
The article according to claim 21. providing a plurality of pellets comprising one or more thermoplastic polymers that are recyclable, biodegradable and/or industrially compostable;
expanding the pellets of the one or more thermoplastic polymers by injecting the pellets with an inert gas;
introducing the expanded pellets into an extruder;
melting the expanded pellets in the extruder;
extruding the molten expanded pellets through a die using an extruder;
Process for producing flexible foam. The one or more thermoplastic polymers are
polybutylene adipate terephthalate (PBAT),
polylactic acid (PLA),
poly(L-lactic acid) (PLLA),
poly(butylene adipate-co-terephthalate) (PBAT),
polycaprolactone (PCL),
polyhydroxyalkanoate (PHA),
polyhydroxybutyrate (PHB),
polybutylene succinate (PBS),
polybutylene succinate adipate (PBSA),
polybutylene adipate (PBA),
thermoplastic starch (TPS),
mixtures containing one or more of them;
comprising a polymer selected from the group consisting of
24. Process according to claim 23. the one or more thermoplastic polymers are PBAT;
24. Process according to claim 23. the one or more thermoplastic polymers are PHAs;
24. Process according to claim 23. the one or more thermoplastic polymers are PHB;
24. Process according to claim 23. the one or more thermoplastic polymers consisting of one or more bio-based polymers;
24. Process according to claim 23. the one or more thermoplastic polymers are reusable polymers;
24. Process according to claim 23. the inert gas is carbon dioxide;
30. A process according to any one of claims 23 to 29. the inert gas is nitrogen,
30. A process according to any one of claims 23 to 29. 30. A foam formed by the process of any one of claims 23-29. the foam is reusable, biodegradable and/or industrially compostable;
33. The foam of claim 32. 33. The foam of claim 32, wherein the foam is free of any crosslinking agent. the article is a footwear component, a seating component, an armor component, a vehicle component, bedding or a water sports accessory;
An article comprising the foam of claim 33.